Understanding color vision deficiency (color blindness)

Color vision deficiency, which you may know as color blindness, is a condition that affects how some people perceive colors.

What is color vision deficiency?

Color vision deficiency is a broad term used to describe a condition where people don’t see colors the way other people do. The term "color blindness" is often used, but true color blindness—where you can’t see any colors at all—is extremely rare. Most people with color vision deficiency can see colors, but have a hard time telling certain colors apart, like red and green. This condition is often caused by the malfunction of what are called “cone” cells in your eye. These cone cells are what allow you to see color.

Color vision deficiency types

There are several common types of color vision deficiency, each defined by which specific cone cells are not working properly.

Red-green color vision deficiency:

This is the most common form of color vision deficiency. It affects how individuals perceive shades of red and green. There are different subtypes, including:

Protanopia:
People with protanopia have no functioning red cones, making it difficult to see red light. They often confuse red with green and perceive other colors differently, especially dark shades.
Deuteranopia:
If you have this type, you lack green cones, leading to similar challenges in distinguishing between reds and greens. Like someone with protanopia, they may also see muted colors more than vibrant hues.
Protanomaly:
This subtype has only partially functioning red cones. As a result, reds may look more like greens, but you may still see some variation in reds depending on brightness.
Deuteranomaly:
Like protanomaly, this condition involves partially functioning green cones. It is the most common form of color vision deficiency and does not usually inhibit a person’s day-to-day life.

Blue-yellow color vision deficiency:

This form is less common and affects the way individuals perceive blue and yellow colors.

Tritanopia:
Individuals with tritanopia lack blue cones altogether. This condition makes it extremely difficult to distinguish between blue and green, and between yellow and red.
Tritanomaly:
This subtype means the blue cones function less effectively, leading to challenges in perceiving blue light. Those with tritanomaly can still see some colors but have difficulty telling the difference between yellow and pink, purple and red, and blue and green.

Complete color vision deficiency (achromatopsia):

This extremely rare condition happens when a person has little to no functioning cone cells, resulting in seeing everything in varying shades of gray. People with this condition often experience additional visual problems, like light sensitivity and poor vision.

What causes color vision deficiency?

Genetics

Most cases of color vision deficiency are hereditary. Inherited color vision deficiency is what’s called a “sex-linked” trait, which is the reason it’s far more common for men to have color vision deficiency than women.

Medical conditions

Conditions like diabetes and glaucoma can cause damage to the retina or optic nerve, leading to difficulties in color perception. Other degenerative diseases, including macular degeneration and multiple sclerosis, may also disturb normal color vision. If a person has an underlying medical condition, their color vision might worsen over time or change unexpectedly. In cases where medical conditions are the cause of color vision deficiency, usually only one eye is affected.

Chemical exposure

Long-term exposure to specific industrial solvents, heavy metals, and some other chemicals has been associated with color vision deficiencies. If you’re commonly exposed to these chemicals, you should always take proper safety precautions, like wearing protective gear and ensuring good ventilation.

Eye injuries

Accidental injuries can damage the retina or optic nerve, both of which are crucial for normal color perception. Seeking immediate medical attention for any eye injuries is important to manage and mitigate any long-term effects on vision, including the ability to perceive color.

Diagnosing color vision deficiency

Diagnosing color vision deficiency typically starts with a comprehensive eye exam conducted by an eye doctor. The most common color vision deficiency test uses what are called “pseudoisochromatic plates.” These are images made of colored dots arranged to form numbers or patterns. Individuals with normal color vision can easily identify the numbers, while those with deficiencies may struggle to identify them correctly. This simple testing method provides quick insights into any visual challenges. If the initial tests indicate a color vision deficiency, more testing may be necessary to fully characterize and diagnose the type and severity of the color vision deficiency.

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Can you treat color vision deficiency?

The treatment for color vision deficiency depends on the diagnosis made by your eye doctor and the approach they recommend. There isn't a cure for color vision deficiency that’s been inherited, but there are things that your eye doctor may recommend to help manage the challenge of not seeing certain colors well. For instance, memorizing the order of colors in important contexts, like the traffic lights, to help with safe driving. Finding a "color buddy"—someone who can help in color-dependent situations—may also be helpful for daily tasks like shopping for clothes or selecting paints. Some people benefit from special glasses or contact lenses that may help boost the contrast between colors they struggle to distinguish.

A comprehensive eye exam is the first step towards diagnosis

While there’s currently no cure for color vision deficiency, it can be comforting to know that you aren’t alone and that there are ways to help manage color vision deficiency. While the condition itself may not significantly disrupt daily life, be sure to discuss any concerns with an eye care professional—they can provide the best guidance on how to manage your own color vision deficiency.

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FAQs

Frequently Asked Questions

What is color vision deficiency?

Color vision deficiency is a visual condition that affects how some people see colors. It’s typically genetic, and can range from mild to severe, impacting your ability to distinguish between certain colors or color combinations.

How is color vision deficiency diagnosed?

The most common way an eye care professional screens for color vision deficiency is by using images made of colored dots but they may use other more specialized tests to accurately differentiate the type and severity.

Can color vision deficiency be treated?

While inherited color vision deficiency has no cure, your doctor may recommend ways to help manage it, like special glasses or contact lenses, memorization tricks, or even apps to help identify colors.

Why is color vision deficiency more common in men?

Most cases of inherited color vision deficiency are linked to a genetic trait located on the X chromosome. Since males have only one X chromosome, they are more likely to exhibit the condition than females, who may be able to compensate for a defect in one X chromosome if their second X chromosome has a normal gene.

Are there any apps to help with color vision deficiency?

There are various apps designed to help with color vision deficiency. Ask your doctor for a recommendation on which would be the best for you to use.

Understanding color vision deficiency (color blindness)

What is color vision deficiency?

Color vision deficiency types

Red-green color vision deficiency:

Blue-yellow color vision deficiency:

Complete color vision deficiency (achromatopsia):

What causes color vision deficiency?

Genetics

Medical conditions

Chemical exposure

Eye injuries

Diagnosing color vision deficiency

Can you treat color vision deficiency?

A comprehensive eye exam is the first step towards diagnosis

Frequently Asked Questions

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